Thiosulfate gold leaching system is regarded as the most promising alternative to cyanide gold leaching because of its low cost,non-toxicity and fast leaching rate.However,there are problems such as the complexity of the leaching system,the unclear mechanism of gold leaching,the dissolution and deposition mechanism of gold that are needed to be further studied,so it is important to study the  mechanism of thiosulfate gold leaching.Based on this,the oxidation mechanism of gold electrode in thiosulfate was studied by means of electrochemical measurement.The oxidation mechanism of gold electrode in different concentrations of thiosulfate solution with pH value of 10.0 was tested by open circuit potential,cyclic voltammetry,Tafel curve and electrochemical impedance spectroscopy.At the same time,the redox reaction of the gold leaching system is discussed.The results showed that the higher the concentration of thio-sulfate,the more conducive to the dissolution of gold,but too high concentration will affect its oxidation rate;high concentration thiosulfate will affect the charge transfer speed,accelerating oxidation rate of gold electrode surface;the electrode oxidation rate is mainly affected by surface oxidation.The study will deepen the understanding of the effect of thiosulfate concentration on gold electrode oxidation mechanism and provide theoretical reference for the practical application of thiosulfate gold leaching.